Abstract/Summary

This report provides a brief introduction to the application of high-pressure liquid chromatography
coupled to inductively coupled plasma mass spectrometry (HPLC-ICP-MS) to determine the
concentration of various arsenic species in water samples. It describes the validation of this arsenic
speciation method developed under the Laboratory Maintenance and Development Capability
Programme to provide data on arsenic speciation in a range of challenging sample matrices to support
BGS science projects and university collaborative research projects.
The validation was carried out in two stages. Firstly, the chromatographic conditions for separating
five arsenic species and coupling of the HPLC to the ICP-MS instrument for subsequent measurement
of arsenic at mass 75 were optimised, together with establishing the stability of standards and
reagents. Once the methodology had been optimised, validation data were obtained based on the
method of Cheeseman and Wilson (Cheeseman & Wilson, 1989).
The measurement of arsenobetaine (AB) and dimethylarsinous acid (DMA) by the proposed
methodology provided good performance data with respect to certified values for the certified
reference material NIES CRM 18 human urine. Performance data obtained for spiked low and high
TDS solutions was generally within acceptance criteria outlined in the validation plan (Appendix 1)
for all of the arsenic species.